Does coral help create rain?

Researchers have found that coral reefs may play a key role in cloud formation. Now they’re working to make climate modelling more accurate.

Australian and international scientists, led by QUT’s Professor Zoran Ristovski, spent a month in late 2016 collecting data on airborne particles emitted from the Great Barrier Reef, which they are now analysing.

Corals produce large amounts of dimethyl sulphide (DMS), a natural aerosol which can form cloud-seeding particles. But when coral is under stress, the amounts it produces varies.

“Aerosol particles play a key role in regulating global climate, by scattering and absorbing radiation from the sun and by taking up water vapour from the atmosphere to start cloud droplet formation,” Zoran says.

Previously, oceanic algae and phytoplankton were thought to be the main marine sources of DMS. Understanding the cloud-forming role of coral will also improve our understanding of how ocean water evaporates, rises, becomes part of a cloud, and falls as rain.

“We still don’t know for sure if coral is a significant source of these particles in the atmosphere over the Reef,” Zoran says.

The team used the Australian Research Vessel Investigator and a mobile, land-based laboratory at Mission Beach to capture the particles.

The project involves researchers from CSIRO, Southern Cross University, Bureau of Meteorology, The University of Melbourne, University of Technology Sydney, National Institute for Environmental Studies (Japan), Fudan University (China), and NIWA and Auckland University (New Zealand).